Extend the hidden-visibility vtables optimization to template classes that
haven't been explicitly instantiated.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@110189 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGVTables.cpp b/lib/CodeGen/CGVTables.cpp
index 052a6fd..9cb64c6 100644
--- a/lib/CodeGen/CGVTables.cpp
+++ b/lib/CodeGen/CGVTables.cpp
@@ -2929,18 +2929,34 @@
// It's okay to have multiple copies of a vtable, so don't make the
// dynamic linker unique them. Suppress this optimization if it's
- // possible that there might be unresolved references elsewhere,
- // which can happen if
- // - there's a key function and the vtable is getting emitted weak
- // anyway for whatever reason
- // - there might be an explicit instantiation declaration somewhere,
- // i.e. if it's a template at all
+ // possible that there might be unresolved references elsewhere
+ // which can only be resolved by this emission.
if (Linkage == llvm::GlobalVariable::WeakODRLinkage &&
VTable->getVisibility() == llvm::GlobalVariable::DefaultVisibility &&
- !RD->hasAttr<VisibilityAttr>() &&
- RD->getTemplateSpecializationKind() == TSK_Undeclared &&
- !CGM.Context.getKeyFunction(RD)) {
- VTable->setVisibility(llvm::GlobalVariable::HiddenVisibility);
+ !RD->hasAttr<VisibilityAttr>()) {
+ switch (RD->getTemplateSpecializationKind()) {
+
+ // Every use of a non-template or explicitly-specialized class's
+ // vtable has to emit it.
+ case TSK_ExplicitSpecialization:
+ case TSK_Undeclared:
+ // Implicit instantiations can ignore the possibility of an
+ // explicit instantiation declaration because there necessarily
+ // must be an EI definition somewhere with default visibility.
+ case TSK_ImplicitInstantiation:
+ // If there's a key function, there may be translation units
+ // that don't have the key function's definition.
+ if (!CGM.Context.getKeyFunction(RD))
+ // Otherwise, drop the visibility to hidden.
+ VTable->setVisibility(llvm::GlobalValue::HiddenVisibility);
+ break;
+
+ // We have to disable the optimization if this is an EI definition
+ // because there might be EI declarations in other shared objects.
+ case TSK_ExplicitInstantiationDefinition:
+ case TSK_ExplicitInstantiationDeclaration:
+ break;
+ }
}
}